<template>
  <div :class="['scroll-wrapper', {'no-scroll': ifNoScroll}, cname]" 
        @scroll.passive="handleScroll" 
        ref="scrollWrapper">
    <slot></slot>
  </div>
</template>

<script>
import { realPx } from '../../utils/common.js'

export default {
  props: {
    cname: {
      type: String,
      default: ''
    },
    top: {
      type: Number,
      default: 0
    },
    bottom: {
      type: Number,
      default: 0
    },
    ifNoScroll: {
      type: Boolean,
      default: false
    },
    initPosition: {
      type: Object,
      default: () => {
        return {
          x: 0,
          y: 0
        }
      }
    }
  },
  methods: {
    handleScroll(e) {
      const offsetY = e.target.scrollTop || window.pageYOffset || document.body.scrollTop
      this.$emit('onScroll', offsetY)
    },
    scrollTo(x, y) {
      this.$refs.scrollWrapper.scrollTo(x, y)
    },
    refresh() {
      if (this.$refs.scrollWrapper) {
        this.$refs.scrollWrapper.style.height = window.innerHeight - realPx(this.top) - realPx(this.bottom) + 'px'
        this.$refs.scrollWrapper.addEventListener('scroll', this.handleScroll)
      }
    }
  },
  mounted() {
    this.refresh()
    this.$nextTick(() => {
      setTimeout(() => {
        this.scrollTo(realPx(this.initPosition.x), realPx(this.initPosition.y))
      }, 1)
    })
  }
}
</script>

<style scoped lang="scss">
.scroll-wrapper {
  position: relative;
  z-index: 100;
  width: 100%;
  overflow-x: hidden;
  overflow-y: scroll;
  -webkit-overflow-scrolling: touch;
  &::-webkit-scrollbar {
    display: none;
  }
  &.no-scroll {
    overflow: hidden;
  }
}
</style>
